Steam-boiler



4Unitarian srA'rns PATENT ruler..

RICH'DnG. BRISTOL, OF CHINA, MICHIGAN.`-

STEAM-BOILER TUBE. .i

Speccation of Letters Patent No. 11,409, dated August 1, 1854.

T all whom t may concern.'

Beit known that I, RICHARD O. BRISTOL, of China, in the county of St'. Clair and State of Michigan, have invented certain new and useful Improvements in the Method of Increasing the Radiating-Surface of Tubes or Plates for Steam-Boilers, Sac.; and

I do hereby declare the following to, be a full, clear, and exact description of the same, reference beinghad to the accompanying drawings, making a part of this specification, in which- Figure 1 represents a view of a chased tube. Fig. 2 represents a longitudinal section through the same. Fig. 3 represents an end view, and Fig. 4 represents a transverse section through the red line fr, y, of Fig. 1.

Similar letters refer to like parts.

This invention is based upon the assumption that heat is increased in proportion to the radiating surface and not in proportion to the fire surface, regardless of the radiating surface, and to distinguish my invention from what has hitherto been done I may mention first that it differs from corrugated plates, inasmuch as corrugations are on both sides of the plate-the plate of uniform thickness throughout, and the corrugations and the bending of the plate into i shape must be at one and the same operaclaim `to the use of corrugated or foldedv plates. I would further remark that the manner in which I apply these chased or embossed surfaces differs materially from anything .heretofore practised.

In Hancocks Narrative, Plate 3, pg.. 13, are represented and described embossed bars between the flues, inthe fire space, for strengthening the tubes. These di'er from my embossings, inasmuch as they are separate fro-m the tubeand neXt the re instead of the water, and the fire surface, but not the radiating surface, is increased thereby. It does not therefore do what I aim at doing. In the patent of Seth Graham, February 15, 1838, screws are cut upon the ends of the tubes, for the purpose of fastening them into their places, not for increasing the radiating surface.` These, too, are in the iire space and not in the water space and do not, if their purpose had been left to conjecture, accomplish what I do. My invention rests upon chasing, embossing, or otherwise roughening that side of the metal next the water, leaving the other side as it is rolled, and thus increase the radiating surface only.

A, represents a tube of the kind claimed, on which a, a, a, are the ridges or prot-uberances, which may be concentric, spiral, or longitudinal, or parts of each. They are most easily prepared by placing them in a lathe and running a Chaser or bur along them, with a suitable thread, or they may be cut or impressed by any other means. Plates also may be treated by :running a tracer or point over their surfaces or rolling them.

Having thus fully described the nature of my invention and shown the difference between it` and those to which it bears an apparent resemblance, what I claim therein as new and desire to secure by Letters Patent is- The cutting, impressing, or otherwise increasing, one of the surfaces of tubes,` or i sheets of metal, which said surface is to form the radiating side of boilers, flues, or vessels, for the purpose of imparting heat to any liquid, vapor, gas, or to atmospheric air when said cutting or impressing is of such a character as to admit of being made after the plates are bent up into form, substantially as described.

R. C. BRISTOL. Witnesses:

A. B. STOUGHTON,

THOMAS I-I. UPPERMAN. 

